Polio has been detected in places it was eliminated. Should we be worried?

A Q&A with Ananda Bandyopadhyay, Deputy Director, Technology, Research, and Analytics

By Dr. Ananda Bandyopadhyay

Deputy Director, Technology, Research, and Analytics, Polio Team, Bill & Melinda Gates Foundation

For The Bill & Melinda Gates Foundation.

Question: Should we be worried about the news out of New York and elsewhere?

Answer: “If you’re fully vaccinated against polio, you have powerful protection against paralysis. Nonetheless, the case in New York, as well as cases of wild polio that were detected in Malawi and Mozambique this year, are warning signals that the virus is now in places where there hadn’t been a detection in many years. It’s a poignant reminder of the vulnerability of the global population and underscores the importance of achieving eradication. If there are pockets of under vaccinated individuals, poliovirus can pop up anywhere as long as the virus exists somewhere.”

Question: “Wild polio.” What does that mean?

Answer: “When we use the term wild polio, we’re referring to the naturally occurring form of the virus. That’s different from a vaccine-derived strain, such as the one that reportedly infected the man in New York. These strains are connected to oral polio vaccines (OPVs), which are a key tool for many countries in the fight against polio and are made from a weakened form of the virus. A vaccinated person can shed that weakened virus, which is actually a good thing, because it can indirectly protect a community.”

“But if there is persistently low immunization coverage in a community—like the part of New York state where the man lived—the weakened virus can circulate for a long time, mutating and acquiring changes in its structure. Rarely, it can regain its ability to induce paralytic outbreaks. But the only right approach to stop vaccine-derived viruses is better vaccination, not stopping vaccine use.

www.gatesfoundation.org/ideas/articles/polio-is-back-in-places-it-was-eliminated-should-we-worry?fbclid=IwAR0TUVfcruwgwn1eRvZ5nXS909nbQapp9XoJ8NPIuJ0VqeJgl3Mldwm1fIk